A spurious correlation between difference scores in evidence-accumulation model parameters

Evidence-accumulation models are a useful tool for investigating the cognitive processes that give rise to behavioural data patterns in reaction times (RTs) and error rates. In their simplest form, evidence-accumulation models include three parameters: The average rate of evidence accumulation over time (drift rate) and the amount of evidence that needs to be accumulated before a response becomes selected (boundary) both characterise the response-selection process; a third parameter summarises all processes before and after the response-selection process (non-decision time). Researchers often compute experimental effects as simple difference scores between two within-subject conditions and such difference scores can also be computed on model parameters. In the present paper, we report spurious correlations between such model parameter difference scores, both in empirical data and in computer simulations. The most pronounced spurious effect is a negative correlation between boundary difference and non-decision difference, which amounts to r = - .70 or larger. In the simulations, we only observed this spurious negative correlation when either (a) there was no true difference in model parameters between simulated experimental conditions, or (b) only drift rate was manipulated between simulated experimental conditions; when a true difference existed in boundary separation, non-decision time, or all three main parameters, the correlation disappeared. We suggest that care should be taken when using evidence-accumulation model difference scores for correlational approaches because the parameter difference scores can correlate in the absence of any true inter-individual differences at the population level.

Rumination and inhibition in task switching: no evidence for an association

Rumination is typically defined as the perseverative focus of attention on negative internal thoughts and feelings, which can increase the risk of developing - and severity once developed - of depression. It is thought the perseveration is caused by a deficit in inhibitory control in ruminators. Congruent with this hypothesis, estimates of inhibition in task switching - the n-2 task repetition cost - are negatively associated with estimates of rumination. However, estimates of individual differences of n-2 task repetition costs are hampered by (a) measurement error caused by trial-wise variation in performance, and (b) recent evidence suggesting much of the n-2 task repetition cost measures interference in episodic memory, not inhibition. The aim of the current study was to revisit the question of the association between the n-2 task repetition cost and measures of rumination by (a) statistically accounting for measurement error by estimating n-2 task repetition costs via trial-level Bayesian multilevel modelling, and (b) controlling for episodic interference effects on estimates of n-2 task repetition cost by utilising a paradigm capable of doing so. The results provided no evidence for an association between rumination and n-2 task repetition costs, regardless of episodic interference.

Computational modelling of attentional selectivity in depression reveals perceptual deficits

BACKGROUND

Depression is associated with broad deficits in cognitive control, including in visual selective attention tasks such as the flanker task. Previous computational modelling of depression and flanker task performance showed reduced pre-potent response bias and reduced executive control efficiency in depression. In the current study, we applied two computational models that account for the full dynamics of attentional selectivity.

METHOD

Across three large-scale online experiments (one exploratory experiment followed by two confirmatory - and pre-registered - experiments; total N = 923), we measured attentional selectivity via the flanker task and obtained measures of depression symptomology as well as anhedonia. We then fit two computational models that account for the dynamics of attentional selectivity: The dual-stage two-phase model, and the shrinking spotlight (SSP) model.

RESULTS

No behavioural measures were related to depression symptomology or anhedonia. However, a parameter of the SSP model that indexes the strength of perceptual input was consistently negatively associated with the magnitude of depression symptomatology.

CONCLUSIONS

The findings provide evidence for deficits in perceptual representations in depression. We discuss the implications of this in relation to the hypothesis that perceptual deficits potentially exacerbate control deficits in depression.

Computational modelling of the speed-accuracy tradeoff: No evidence for an association with depression symptomatology

Successful decision making often requires finding the right balance between the speed and accuracy of responding: Emphasising speed can lead to error-prone performance, yet emphasising accuracy leads to a slowing of performance. Such speed-accuracy tradeoffs (SATs) therefore require establishing appropriate response settings to optimise performance in response to changing environmental demands. Such strategic adaptation of response settings relies on the striatum component of the basal ganglia, an area implicated in depression. The current study explored the association between depression symptomatology and SAT performance. Two experiments presented participants with an SAT paradigm embedded within a simple decision-making task, together with measures of depression symptomatology. Experiment 1 (N = 349) was correlational, whereas Experiment 2 was a two-phase experiment where participants (N = 501) were first pre-screened on depression symptomatology and extreme-low and extreme-high responders (total N = 91) were invited to Phase 2. Behavioural data were modelled with a drift diffusion model. Behavioural data and associated diffusion modelling showed large and robust SAT effects. Emphasising accuracy led to an increase in boundary separation, an increase in drift rate, and an increase in non-decision time. However, the magnitude of the changes of these parameters with SAT instructions was not associated with measures of depression symptomatology. The results suggest that the strategic adaptation of response settings in response to environmental changes in speed-accuracy instructions does not appear to be associated with depression symptomatology.

Improving research quality: the view from the UK Reproducibility Network institutional leads for research improvement

The adoption and incentivisation of open and transparent research practices is critical in addressing issues around research reproducibility and research integrity. These practices will require training and funding. Individuals need to be incentivised to adopt open and transparent research practices (e.g., added as desirable criteria in hiring, probation, and promotion decisions, recognition that funded research should be conducted openly and transparently, the importance of publishers mandating the publication of research workflows and appropriately curated data associated with each research output). Similarly, institutions need to be incentivised to encourage the adoption of open and transparent practices by researchers. Research quality should be prioritised over research quantity. As research transparency will look different for different disciplines, there can be no one-size-fits-all approach. An outward looking and joined up UK research strategy is needed that places openness and transparency at the heart of research activity. This should involve key stakeholders (institutions, research organisations, funders, publishers, and Government) and crucially should be focused on action. Failure to do this will have negative consequences not just for UK research, but also for our ability to innovate and subsequently commercialise UK-led discovery.

Exploring the Impact of Mindfulness on False-Memory Susceptibility

Wilson, Mickes, Stolarz-Fantino, Evrard, and Fantino (2015) presented data from three well-powered experiments suggesting that a brief mindfulness induction can increase false-memory susceptibility. However, we had concerns about some of the methodology, including whether mind wandering is the best control condition for brief mindfulness inductions. Here, we report the findings from a preregistered double-blind randomized controlled trial designed to replicate and extend Wilson et al.'s findings. Participants (N = 287) underwent 15-min mindfulness or mind-wandering inductions or completed a join-the-dots task before being presented with lists of words related to nonpresented critical lures. This was followed by free-recall and recognition tasks. There was no evidence for an effect of state of mind on correct or false recall or recognition. Furthermore, manipulation checks revealed that mindfulness and mind-wandering inductions activated overlapping states of mind. Exploratory analyses provided some support for mindfulness increasing false memory, but it appears that mind wandering may not be the right control for brief mindfulness research.

The Effect of Aging on Response Congruency in Task Switching: A Meta-Analysis

OBJECTIVES

Response-congruency effects in task switching are the observed slowing of response times (RTs) for incongruent targets which afford more than one response (depending on task) in comparison to congruent stimuli that afford just one response regardless of the task. These effects are thought to reflect increased ambiguity during response selection for incongruent stimuli.

METHODS

The present study presents a meta-analysis of 27 conditions (from 16 separate studies) whose designs allowed investigation of age-related differences in response-congruency effects on RT.

RESULTS

Multilevel modelling of Brinley plots and state-trace plots showed no age-related effect on response congruency beyond that which can be explained by general age-related slowing.

DISCUSSION

The results add to the growing body of evidence of no age-related decline in measures of attention and executive functioning.

The effect of episodic retrieval on inhibition in task switching: a diffusion model analysis

Inhibition in task switching is inferred from \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n-2$$\end{document}n-2 task repetition costs: slower response times and poorer accuracy for ABA task switching sequences compared to CBA sequences, thought to reflect the persisting inhibition of task A across an ABA sequence. Much work has examined the locus of this inhibition effect, with evidence that inhibition targets response selection processes. Consistent with this, fits of the diffusion model to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n-2$$\end{document}n-2 task repetition cost data have shown that the cost is reflected by lower estimates of drift rate, suggesting that inhibition impairs information processing efficiency during response selection. However, we have shown that the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n-2$$\end{document}n-2 task repetition cost is confounded with episodic retrieval effects which masquerade as inhibitory costs. The purpose of the current study was to conduct a comprehensive analysis of diffusion model fits to new data within a paradigm that controls for episodic interference. Across four experiments (total \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$N = 191$$\end{document}N=191), we find evidence that the reduction of drift rate for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n-2$$\end{document}n-2 task repetition costs is only evident under conditions of episodic interference, and the cost is absent when this interference is controlled for. In addition, we also find evidence that episodic retrieval influences task preparation processes and response caution. These findings provide important constraints for theories of task switching that suggest inhibition selectively targets response selection processes.

Does Task Activation in Task Switching Influence Inhibition or Episodic Interference?

N-2 repetition costs in task switching refer to slower responses to ABA sequences compared to CBA sequences, reflecting the persisting inhibition of task A across the ABA sequence. The magnitude of inhibition is thought to be sensitive to activation levels of interfering tasks. This is supported by larger n-2 repetition costs when the response-cue interval (RCI) is reduced: At short RCIs, a just-performed task is highly active when a new task is required, triggering more inhibition. However, recent work has shown that much of the n-2 repetition cost measures episodic interference, rather than inhibition. The current study addressed whether RCI manipulations influence inhibition or episodic interference. N-2 repetition costs were considerably reduced when episodic interference was controlled. Increasing the RCI led to equivalent reductions in the n-2 repetition cost for inhibition and episodic components of the cost, but for the former, the cost was entirely absent at longer RCIs.

The effect of practice on inhibition in task switching: Controlling for episodic retrieval

Previous work has shown that extended practice leads to a reduction in a key measure of cognitive inhibition during task switching: The n-2 task repetition cost. However, it has been demonstrated that this n-2 task repetition cost is increased by a non-inhibitory process-namely episodic retrieval-raising the question of whether the observed reduction of the cost with practice is driven by a reduction in inhibition, episodic retrieval effects, or a combination of both. The current study addresses this question by utilising a practice protocol using a task switching paradigm capable of controlling for episodic retrieval. The results showed a reduction in the n-2 task repetition cost with extended practice. The results also showed a clear increase of the n-2 task repetition cost due to episodic retrieval effects. The reduction of the cost with practice was driven by a reduction in inhibition and episodic retrieval contributions to the cost with practice, although there was a larger reduction in the episodic retrieval contribution with practice. The results are discussed with reference to current theoretical models of inhibition in task switching, which need to accommodate episodic retrieval and practice effects.

Impulse Control Disorder in Parkinson's Disease: A Meta-Analysis of Cognitive, Affective, and Motivational Correlates

Background: In Parkinson's disease (PD), impulse control disorders (ICDs) develop as side-effect of dopaminergic replacement therapy (DRT). Cognitive, affective, and motivational correlates of ICD in medicated PD patients are debated. Here, we systematically reviewed and meta-analyzed the evidence for an association between ICD in PD and cognitive, affective, and motivational abnormalities. Methods: A systematic review and meta-analysis was performed on PubMed, Science Direct, ISI Web of Science, Cochrane, EBSCO for studies published between 1-1-2000 and 8-3-2017 comparing cognitive, affective, and motivational measures in PD patients with ICD (ICD+) vs. those without ICD (ICD-). Exclusion criteria were conditions other than PD, substance and/or alcohol abuse, dementia, drug naïve patients, cognition assessed by self-report tools. Standardized mean difference (SMD) was used, and random-effect model applied. Results: 10,200 studies were screened (title, abstract), 79 full-texts were assessed, and 25 were included (ICD+: 625 patients; ICD-: 938). Compared to ICD-, ICD+ showed worse performance reward-related decision-making (0.42 [0.02, 0.82], p = 0.04) and set-shifting tasks (SMD = -0.49 [95% CI -0.78, -0.21], p = 0.0008). ICD in PD was also related to higher self-reported rate of depression (0.35 [0.16, 0.54], p = 0.0004), anxiety (0.43 [0.18, 0.68], p = 0.0007), anhedonia (0.26 [0.01, 0.50], p = 0.04), and impulsivity (0.79 [0.50, 1.09], p < 0.00001). Heterogeneity was low to moderate, except for depression (I² = 61%) and anxiety (I² = 58%). Conclusions: ICD in PD is associated with worse set-shifting and reward-related decision-making, and increased depression, anxiety, anhedonia, and impulsivity. This is an important area for further studies as ICDs have negative impact on the quality of life of patients and their caregivers.

Increased cognitive control after task conflict? Investigating the N-3 effect in task switching

Task inhibition is considered to facilitate switching to a new task and is assumed to decay slowly over time. Hence, more persisting inhibition needs to be overcome when returning to a task after one intermediary trial (ABA task sequence) than when returning after two or more intermediary trials (CBA task sequence). Schuch and Grange (J Exp Psychol Learn Mem Cogn 41:760-767, 2015) put forward the hypothesis that there is higher task conflict in ABA than CBA sequences, leading to increased cognitive control in the subsequent trial. They provided evidence that performance is better in trials following ABA than following CBA task sequences. Here, this effect of the previous task sequence ("N-3 effect") is further investigated by varying the cue-stimulus interval (CSI), allowing for short (100 ms) or long (900 ms) preparation time for the upcoming task. If increased cognitive control after ABA involves a better preparation for the upcoming task, the N-3 effect should be larger with long than short CSI. The results clearly show that this is not the case. In Experiment 1, the N-3 effect was smaller with long than short CSI; in Experiment 2, the N-3 effect was not affected by CSI. Diffusion model analysis confirmed previous results in the literature (regarding the effect of CSI and of the ABA-CBA difference); however, the N-3 effect was not unequivocally associated with any of the diffusion model parameters. In exploratory analysis, we also tested the alternative hypothesis that the N-3 effect involves more effective task shielding, which would be reflected in reduced congruency effects in trials following ABA, relative to trials following CBA; congruency effects did not differ between these conditions. Taken together, we can rule out two potential explanations of the N-3 effect: Neither is this effect due to enhanced task preparation, nor to more effective task shielding.

The effect of episodic retrieval on inhibition in task switching

Inhibition in task switching is inferred from n-2 repetition costs: the observation that ABA task switching sequences are responded to slower than CBA sequences. This is thought to reflect the persisting inhibition of Task A, which slows reactivation attempts. Mayr (2002) reported an experiment testing a critical noninhibitory account of this effect, namely episodic retrieval: If the trial parameters for Task A match across an ABA sequence, responses should be facilitated because of priming from episodic retrieval; a cost would occur if trial parameters mismatch. In a rule-switching paradigm, Mayr reported no significant difference in n-2 repetition cost when the trial parameters repeated or switched across an ABA sequence, in clear contrast to the episodic retrieval account. What remains unclear is whether successful episodic retrieval modulates the n-2 repetition cost. Across 3 experiments-including a close replication of Mayr-we find clear evidence of reduced n-2 task repetition costs when episodic retrieval is controlled. We find that the effect of episodic retrieval on the n-2 task repetition cost is increased when the cue-task relationship is made more abstract, suggesting the effect is because of interference in establishing the relevant attentional set. We also demonstrate that the episodic retrieval effect is not influenced by retrieval of low-level, perceptual, elements. Together, the data suggest the n-2 task repetition cost-typically attributable to an inhibitory mechanism-also reflects episodic retrieval effects. (PsycINFO Database Record

Does familial risk for alcohol use disorder predict alcohol hangover?

AIMS

Positive family history of alcohol use disorder (FHP), a variable associated with propensity for alcohol use disorder (AUD), has been linked with elevated hangover frequency and severity, after controlling for alcohol use. This implies that hangover experiences may be related to AUD. However, inadequate control of alcohol consumption levels, low alcohol dose and testing for hangover during the intoxication phase detract from these findings. Here, we present further data pertinent to understanding the relationship between family history and alcohol hangover.

METHODS

Study 1 compared past year hangover frequency in a survey of 24 FHP and 118 family history negative (FHN) individuals. Study 2 applied a quasi-experimental naturalistic approach assessing concurrent hangover severity in 17 FHP and 32 FHN individuals the morning after drinking alcohol. Both studies applied statistical control for alcohol consumption levels.

RESULTS

In Study 1, both FHP status and estimated blood alcohol concentration on the heaviest drinking evening of the past month predicted the frequency of hangover symptoms experienced over the previous 12 months. In Study 2, estimated blood alcohol concentration the previous evening predicted hangover severity but FHP status did not.

CONCLUSIONS

FHP, indicating familial risk for AUD, was not associated with concurrent hangover severity but was associated with increased estimates of hangover frequency the previous year.

Inhibition in task switching: The reliability of the n - 2 repetition cost

The n - 2 repetition cost seen in task switching is the effect of slower response times performing a recently completed task (e.g. an ABA sequence) compared to performing a task that was not recently completed (e.g. a CBA sequence). This cost is thought to reflect cognitive inhibition of task representations and as such, the n - 2 repetition cost has begun to be used as an assessment of individual differences in inhibitory control; however, the reliability of this measure has not been investigated in a systematic manner. The current study addressed this important issue. Seventy-two participants performed three task switching paradigms; participants were also assessed on rumination traits and processing speed-measures of individual differences potentially modulating the n - 2 repetition cost. We found significant n - 2 repetition costs for each paradigm. However, split-half reliability tests revealed that this cost was not reliable at the individual-difference level. Neither rumination tendencies nor processing speed predicted this cost. We conclude that the n - 2 repetition cost is not reliable as a measure of individual differences in inhibitory control.

A deficit in familiarity-driven recognition in a right-sided mediodorsal thalamic lesion patient

OBJECTIVE

According to a still-controversial view of recognition, projections between the perirhinal cortex and the medial subdivision of the mediodorsal thalamic nucleus (mMDT) support the mnemonic processes underlying familiarity, whereas a separate extended hippocampal system is critical for the recollection of episodic details during recognition.

METHOD

In this study, we examined item recognition, familiarity, and recollection for faces and words in a patient (OG) with a right-sided lesion centered on the mMDT, which encroached on the central medial midline nucleus and may have resulted in partial disconnection of the mammillothalamic tract. On the basis of OG's neuropathology, the dual-process signal-detection (DPSD) high-threshold theory and the material-specific hypothesis of long-term memory together predicted a material-specific impairment in familiarity for novel facial memoranda, with a lesser decline in recollection of novel faces at short retention intervals. No abnormalities in either familiarity- or recollection-driven recognition of verbal memoranda were expected.

RESULTS

Comparing the performance of OG and that of a group of 10 age-, sex-, and IQ-matched healthy controls, the remember-know procedure revealed the dissociations predicted by the material-specific and DPSD hypotheses: With recognition of previously novel faces, OG showed a deficit in familiarity-driven recognition that was significantly greater than the insignificant reduction in his recollection. All components of his word recognition were, however, preserved.

CONCLUSION

A memory profile, marked by a dissociation between familiarity and recollection, fits naturally with the DPSD model and is incompatible with the idea that these kinds of memories reflect different degrees of trace strength.

The effect of alcohol hangover on choice response time

The effect of alcohol hangover on cognitive processing has received little attention. We explored the effect of alcohol hangover on choice response time (RT), a dominant dependent variable (DV) in cognitive research. Prior research of the effect of hangover on RT has produced mixed findings; all studies reviewed relied exclusively on estimates of central tendency (e.g. mean RT), which has limited information value. Here we present novel analytical methods by going beyond mean RT analysis. Specifically, we examined performance in hangover conditions (n=31) across the whole RT distribution by fitting ex-Gaussian models to participant data, providing a formal description of the RT distribution. This analysis showed detriments to performance under hangover conditions at the slower end of the RT distribution and increased RT variance under hangover conditions. We also fitted an explicit mathematical process model of choice RT - the diffusion model - which estimates parameters reflecting psychologically-meaningful processes underlying choice RT. This analysis showed that hangover reduced information processing efficiency during response selection, and increased response caution; changes in these parameters reflect hangover affecting core decisional-components of RT performance. The implications of the data as well as the methods used for hangover research are discussed.

Response to Comment on "Estimating the reproducibility of psychological science"

Gilbert et al. conclude that evidence from the Open Science Collaboration's Reproducibility Project: Psychology indicates high reproducibility, given the study methodology. Their very optimistic assessment is limited by statistical misconceptions and by causal inferences from selectively interpreted, correlational data. Using the Reproducibility Project: Psychology data, both optimistic and pessimistic conclusions about reproducibility are possible, and neither are yet warranted.

Temporal Distinctiveness in Task Switching: Assessing the Mixture-Distribution Assumption

In task switching, increasing the response–cue interval has been shown to reduce the switch cost. This has been attributed to a time-based decay process influencing the activation of memory representations of tasks (task-sets). Recently, an alternative account based on interference rather than decay has been successfully applied to this data (Horoufchin et al., 2011a). In this account, variation of the RCI is thought to influence the temporal distinctiveness (TD) of episodic traces in memory, thus affecting their retrieval probability. This can affect performance as retrieval probability influences response time: If retrieval succeeds, responding is fast due to positive priming; if retrieval fails, responding is slow, due to having to perform the task via a slow algorithmic process. This account—and a recent formal model (Grange and Cross, 2015)—makes the strong prediction that all RTs are a mixture of one of two processes: a fast process when retrieval succeeds, and a slow process when retrieval fails. The present paper assesses the evidence for this mixture-distribution assumption in TD data. In a first section, statistical evidence for mixture-distributions is found using the fixed-point property test. In a second section, a mathematical process model with mixture-distributions at its core is fitted to the response time distribution data. Both approaches provide good evidence in support of the mixture-distribution assumption, and thus support temporal distinctiveness accounts of the data.

The effect of practice on n-2 repetition costs in set switching

Inhibition in set switching is inferred from so-called n-2 repetition costs: slower response times to ABA sequences compared to CBA sequences (where A, B, and C are arbitrary labels for different tasks). These costs are thought to reflect the persisting inhibition of task A when it was disengaged recently (as is the case in an ABA sequence). In this study we were interested in whether more inhibition may be required when the tasks are relatively novel. To this end, we examined the effect of practice on the n-2 repetition cost in nine participants across five experimental sessions, with 1222 trials performed in each session. The results show a clear reduction in the n-2 repetition cost, being altogether absent from the final sessions. Such a reduction is predicted by both: (a) a recent computational model of the n-2 repetition cost (Grange, Juvina, & Houghton, 2013) due to the gradual strengthening of task-related memory elements with practice to the point where inhibition has less impact; and (b) prior work showing smaller n-2 repetition costs with greater cue-target association strength (Houghton, Pritchard, & Grange, 2009). In this paper, we integrate these two theoretical derivations by extending our computational model, which fit the current data-at the mean level, block level, and individual-subject (i.e., individual differences) level-well.

Can time-based decay explain temporal distinctiveness effects in task switching?

In task switching, extending the response–cue interval (RCI) reduces the switch cost—the detriment to performance when switching compared to repeating tasks. This reduction has been used as evidence for the existence of task-set decay processes. Recently, this has been challenged by the observation of sequential dependencies on the RCI effect: switch cost is only reduced at longer RCIs when the previous trial had a short RCI. This trial-wise variation of RCI is thought to affect the temporal distinctiveness (TD) of a previous task's episodic trace, affecting the probability of its automatic retrieval on the current trial; importantly, TD is thought to be independent of the current trial's RCI. The present study highlights a dependency between the current RCI and TD, and demonstrates that a decay model can reproduce some patterns of data attributed to TD. Further, the decay account makes a strong prediction when TD is held constant: repetition response times should slow as the RCI increases, and switch response times should be facilitated. This prediction was tested via re-analysis of extant data and three experiments. The re-analysis provided some evidence for the decay account, but Experiments 1 and 2 report slowing for task repetition and switch trials, which cannot be explained by a task-set decay process. Experiment 3, which utilized tasks requiring perceptual judgements, showed small evidence for decay. We conclude that the data are largely consistent with the TD account and that the evidence for decay of higher-level task-sets is not convincing.

The effect of N-3 on N-2 repetition costs in task switching

N-2 task repetition cost is a response time and error cost returning to a task recently performed after one intervening trial (i.e., an ABA task sequence) compared with returning to a task not recently performed (i.e., a CBA task sequence). This cost is considered a robust measure of inhibitory control during task switching. The present article reports a novel sequential effect of n-2 task repetitions when trial n-3 is taken into consideration. In particular, performance is better in trials preceded by an n-2 repetition than in trials preceded by an n-2 switch. That is, performance is better in BABA sequences (where trial n-1 was an n-2 repetition) than in CABA sequences (where trial n-1 was an n-2 switch). Likewise, performance is better in BCBA (where trial n-1 was an n-2 repetition) than in ACBA or DCBA sequences (where trial n-1 was an n-2 switch). Evidence for this new n-3 effect is provided by a mini meta-analysis of a set of published data, as well as 2 new experiments applying a different paradigm. We suggest that this new effect reflects trial-by-trial modulation of cognitive control: Task conflict is higher in n-2 repetitions than in n-2 switches; therefore, cognitive control is increased in trials following n-2 repetitions, leading to improved performance. This facilitating effect of previous task conflict is discussed with respect to current theories on cognitive control.

A critical analysis of alcohol hangover research methodology for surveys or studies of effects on cognition

RATIONALE

Alcohol hangover may be defined as an adverse effect of heavy alcohol consumption present after sufficient time has elapsed for the alcohol to have been eliminated from the blood. Understanding how hangover may impair performance is important for public safety; yet, there is relatively little hangover research. This paper outlines good practice for future studies.

OBJECTIVES

This paper presents a critical analysis of hangover methodology for surveys or studies of effects on cognition with human subjects and provides suggestions for optimum research practice for laboratory-based and naturalistic alcohol hangover studies.

RESULTS

Four hangover symptom scales have been developed and subjected to psychometric testing. For retrospective assessment, we recommend the Hangover Symptoms Scale (HSS) or the Alcohol Hangover Severity Scale (AHSS). For concurrent assessment of hangover symptoms, we recommend either the Acute Hangover Scale (AHS), the five-item version of the HSS, or the AHSS. In research aiming to assess the cognitive effects of alcohol hangover, we suggest focusing on the cognitive domains of attention, memory and executive function, and we specify a number of tests within these cognitive domains that are likely to be sensitive to any decrements due to hangover. Finally, we argue that naturalistic studies should assess biological markers to improve the accuracy of estimates of alcohol consumption. Specifically, we recommend the assessment of ethyl glucuronide (EtG) for this purpose.

CONCLUSIONS

Recommendations are made with respect to assessing hangover symptoms, cognitive effects of hangover and biological markers of alcohol consumption.

Heightened conflict in cue-target translation increases backward inhibition in set switching

Backward inhibition (BI) is a performance cost that occurs when an individual returns to a task after 1 (vs. more than 1) intervening trial, and it may reflect the inhibition of task-set components during switching. In 3 experiments, we support the theory that inhibition can target cue-based preparatory stages of a task. Participants performed a cued target-localization task that had been previously shown to produce BI. In Experiment 1, reassignment of arbitrary cue-target pairings midway through the experiment doubled the size of BI, though cue, target, and response sets remained unchanged. In Experiment 2, we controlled for effects of order of conditions or simple change of cue meaning. In Experiment 3, we demonstrated that the effect depends on re-pairing members of the same cue and target sets. The results are attributed to heightened conflict (and hence greater inhibition) during cue-target translation when a previously learned cue-target mapping is remapped.

Temporal cue–target overlap is not essential for backward inhibition in task switching

Lag 2 repetition costs are a performance cost observed when participants return to a task after just one intervening trial of a different task, compared to returning after a longer interval (AB A vs. CB A sequences, where A, B, C are tasks). This effect is known as backward inhibition (BI) and is thought to reflect the need to overcome inhibition applied specifically to Task “A” during disengagement at trial n – 1. Druey and Hübner (2007) have suggested that employment of such a specific inhibitory mechanism relies upon the cue and the target of the task overlapping temporally. We provide evidence across three experiments (including a direct replication attempt) that this is not the case, and that the presence of task-specific BI relies to some extent on the need to translate the cue–target relationship into working memory. Additionally, we provide evidence that faster responses in no overlap conditions are driven by low-level perceptual differences between target displays across overlap conditions. We conclude that BI is an effective sequential control mechanism, employed equally in cases of temporally overlapping and temporally separated cues and targets.